Legal Review

• Reviewed on: September 5, 2026
• Attorney: James G. Burns, Esq., LL.M.
• Credentials: TEP (Trust and Estate Practitioner), Member of STEP; Selected to Super Lawyers 2022–2027 (5 consecutive years); Top-Rated Lawyer (Avvo 2021); America's Most Honored Lawyers (2020)

The Short Answer

It depends on the authority you hold and the capacity your spouse retains. Marriage alone doesn't give one spouse the right to rewrite a trust or unilaterally move assets. The answer turns on how the assets are titled, what the trust says about amendment, whether your spouse still understands the proposed change, and what authority a durable power of attorney or court order gives you. California law recognizes that a person with dementia may still have capacity for some decisions. A diagnosis, by itself, doesn't settle the question. There may be lawful steps available now, but they're specific and fact-sensitive. Move carefully. A rushed amendment, transfer, or account change can later be challenged, unwound, or treated as a breach of duty.

Key Takeaways

• A spouse doesn't automatically have authority to amend the other spouse's revocable trust.
• A financial power of attorney allows only the powers granted by the document and applicable law.
• Joint ownership and community-property rules are different questions from trust-amendment authority.
• A court may approve certain changes through a conservatorship and substituted-judgment petition.
• Start with the trust, power of attorney, account titles, deeds, and current medical information before moving assets.

Who This Applies To

This article is for California spouses of people with dementia or another form of incapacity, adult children assisting parents, caregivers, trustees, and agents acting under financial powers of attorney.

It commonly applies when a family is considering:

• Changing a joint or separate revocable trust
• Removing or replacing a beneficiary
• Selling or refinancing a jointly owned home
• Moving money between accounts
• Funding a new trust for long-term-care or Medi-Cal planning
• Replacing a trustee who can no longer manage trust property

This is an area where compassion and precision must work together. Dementia can progress gradually, and capacity can vary from day to day. The legal question is not simply, “Does this person have dementia?” The question is whether the person had the capacity required for the particular act at the relevant time.

The Five Sources of Authority

The trust instrument

Start with the trust itself and every amendment.

The document may explain:

• Who may amend or revoke the trust
• Whether each settlor controls only that settlor's property
• Whether one spouse may act for the other
• What happens if a settlor becomes incapacitated
• How a successor trustee is appointed
• Whether the trust restricts an agent or conservator from making changes

Under Probate Code § 15401, an attorney-in-fact generally may not modify or revoke a trust unless the trust instrument expressly permits it. A power of attorney doesn't automatically override the trust.

The durable power of attorney

A financial power of attorney may allow an agent to manage bank accounts, real property, investments, or business interests. The scope depends on the document's language, execution, and effective date.

Review whether the power is:

• Immediate or springing
• Durable after incapacity
• Limited to specific transactions
• Broad enough to address gifts or trust funding
• Silent about trust amendment or revocation

A statutory form power of attorney under Probate Code § 4401 is not a blank check. The agent must act within the granted authority and in the principal's interest. Unless the trust expressly allows it, the agent generally cannot rewrite the principal's estate plan.

A health-care directive under Probate Code § 4701 addresses health-care decisions. It doesn't ordinarily authorize financial transfers or trust amendments.

Joint ownership terms

Joint ownership may allow one owner to access or manage an account, but access isn't the same as ownership of the other person's interest.

A joint tenant may have authority to deal with that person's own interest, but a unilateral transaction can affect survivorship rights, sever the joint tenancy, create tax consequences, or trigger a dispute over whether the transaction was authorized.

Read the deed, account agreement, beneficiary designation, and trust schedule together. Don't rely on the word “joint” alone.

Community-property rules

California spouses generally share management rights over community personal property. But those rights have limits.

Family Code § 1100 addresses management and control of community personal property, restrictions on gifts or transfers for less than fair value, the family dwelling, and each spouse's fiduciary duties of disclosure and fair dealing.

Community property analysis is separate from trust analysis. An asset can be community property, titled jointly, held in a trust, or subject to more than one of these classifications at the same time.

Court authority

If a spouse can no longer act personally and existing documents don't provide enough authority, a conservatorship may be required.

Under Probate Code § 2580, a conservator or other interested person may petition for authority to take actions benefiting the conservatee or estate, minimizing taxes or administration expenses, or making gifts that the conservatee would likely have made.

The statute can address creating or funding trusts, changing beneficiary rights, transferring property, and exercising rights connected to a revocable trust. The trust's language still matters. The court must evaluate the proposed action and the conservatee's probable intent.

Capacity Is Specific to the Act

California law begins with a presumption that people have capacity. Probate Code § 810 also makes clear that a diagnosis alone doesn't establish incapacity.

The relevant inquiry may include whether the person could:

• Understand the nature and effect of the proposed document
• Understand the property involved
• Appreciate the people affected by the change
• Understand the consequences of changing beneficiaries or ownership
• Communicate a consistent decision

Probate Code § 811 focuses on functional mental deficits and their connection to the decision. Capacity may be transaction-specific and time-specific. Someone may be able to consent to ordinary medical care but not understand a complex trust amendment.

Document the process carefully. Obtain appropriate professional input, avoid coaching, and preserve contemporaneous records.

Three Hypothetical Examples

Hypothetical only: Removing a child from a shared trust

A wife wants to amend a joint trust after her husband develops dementia. She wants to remove one of their children as a beneficiary.

First determine whether the husband is a settlor, whether the trust permits unilateral amendment, and whether he still has the capacity to approve the change. If he lacks capacity, the wife's marriage and trustee status may not be enough. An agent may also lack authority unless the trust expressly permits amendment under the power of attorney.

Removing a child from an estate plan can create a later contest, particularly where the child is from an earlier relationship. Proceed only after reviewing capacity, undue-influence risks, fiduciary duties, and the precise trust language.

Hypothetical only: Selling a jointly held house to fund care

A husband wants to sell the family home to pay for memory-care expenses.

The analysis includes title, community-property character, the deed, the trust, the spouse's rights, and the financial power of attorney. A sale may be possible, but the husband may not have authority to convey his wife's interest merely because he is her spouse or co-owner.

If authority is missing, a court proceeding may be necessary. Do not sign closing documents first and investigate authority later.

Hypothetical only: Funding a Medi-Cal planning trust

An adult child holds a parent's financial power of attorney and wants to move assets into a Medicaid Asset Protection Trust for future Medi-Cal planning.

That transaction requires careful review of the power of attorney, the parent's intent, timing, transfer consequences, existing obligations, and eligibility rules. A power of attorney should not be used to defeat creditors, evade duties, or make transfers the principal would not have approved.

Medi-Cal planning is not a magic solution. A transfer may affect eligibility, control, taxes, long-term-care payment responsibility, and family relationships. Coordinate elder-law and tax advice before moving assets.

Common Mistakes to Avoid

• Assuming marriage grants unilateral authority
• Treating a dementia diagnosis as automatic incapacity
• Amending a trust without a defensible capacity process
• Having an agent act beyond the express power of attorney
• Moving assets after capacity is genuinely gone without court authority
• Ignoring the incompetent spouse's community-property interest
• Treating account access as ownership authority
• Disinheriting a child from an earlier marriage without heightened care
• Failing to preserve the original trust, amendments, deeds, and account records
• Confusing trustee administration with authority to change beneficial interests

A trustee may administer trust property without having power to rewrite the trust. If a trustee becomes substantially unable to manage trust resources or resist undue influence, Probate Code § 15642 provides a possible route for removal through the trust instrument or court petition.

What May Still Be Done While Capacity Remains

If your spouse retains sufficient capacity, act deliberately:

1. Review the current trust and all amendments.
2. Confirm who owns each asset and how it is titled.
3. Evaluate capacity for the specific proposed transaction.
4. Consider updated beneficiary designations and other documents while the person can understand them.
5. Coordinate with the person's physician and independent legal counsel.
6. Avoid having an interested beneficiary dominate the process.
7. Consider conservatorship or substituted judgment if existing authority is incomplete.
8. Address long-term-care planning before an emergency forces rushed decisions.

If you're beginning this review in Orange County or elsewhere in Southern California, start with the firm's estate-planning resources and bring the actual documents, not summaries or recollections. Additional planning information is available through the firm's client command resource.

When It May Be Too Late

Once capacity is substantially gone and no adequate power of attorney or trust provision exists, the family may need a conservatorship. A substituted-judgment petition may then ask the court to authorize a transaction, trust change, gift, or other action.

A transfer made without authority may be challenged or unwound. The person making the decision may face claims for breach of fiduciary duty, undue influence, or misuse of assets. Timing, medical records, witness evidence, financial records, and the original documents can become critical.

A Practical Document Checklist

Gather:

• The complete trust instrument and every amendment
• The financial power of attorney
• The advance health-care directive
• Deeds and title reports
• Bank, brokerage, retirement, and insurance statements
• Beneficiary designation forms
• Business ownership records
• Physician evaluations and capacity notes
• A written list of the intended changes
• A record of recent transfers, gifts, and unusual transactions

Tactical FAQ

Can I change our trust if my spouse has dementia?

Possibly, but dementia alone doesn't answer the question. Review the trust, determine whether your spouse still has capacity for the proposed amendment, and confirm whether any agent has express authority. If capacity is absent and the documents don't provide authority, court approval may be required.

Does marriage give me authority over joint assets?

No. Marriage may affect community-property rights and management, but it doesn't automatically authorize one spouse to change the other spouse's trust or transfer the other spouse's ownership interest. Review title, the deed, the trust, and Family Code § 1100 together.

What can a power of attorney actually do?

A power of attorney permits an agent to act within the authority granted by the document and applicable law. It may support financial management, but it doesn't automatically authorize gifts, trust amendments, or changes to the principal's estate plan.

What is a substituted-judgment petition?

It's a court petition asking for authority to take a proposed action for a conservatee, such as creating or funding a trust, changing a beneficiary, or modifying a revocable trust. The court evaluates the conservatee's interests and probable wishes under Probate Code § 2580.

What if my spouse can no longer sign anything?

Don't assume that no signature means no options. Review the trust and power of attorney immediately. If existing documents don't provide sufficient authority, a conservatorship and possible substituted-judgment petition may be necessary.

A Careful Next Step

Request a Situation Readiness Briefing as a diagnostic review. Bring the trust, amendments, powers of attorney, deeds, account statements, and beneficiary forms. The first task is to map capacity, authority, ownership, and risk before anyone moves an asset or signs a new document.

You can also review the firm's asset-protection practice and the additional planning resource at the Law Office of James Burns command site. Options often narrow over time, but careful analysis is more important than rushing.

Resources and Authorities

• California Probate Code § 15401: Revocation of trusts
• California Probate Code §§ 810–812: Capacity and functional deficits
• California Probate Code § 4401: Statutory form power of attorney
• California Probate Code § 4701: Advance health-care directive form
• California Probate Code § 15642: Trustee removal
• California Probate Code § 2580: Substituted judgment
• California Probate Code §§ 2600 et seq.: Conservatorship provisions
• California Family Code § 1100: Management and control of community property
• California Probate Code §§ 100 and 102: General statutory context

Author

James G. Burns, Esq., LL.M., is the founder of the Law Office of James Burns in Orange County, California. He focuses on advanced estate planning, asset protection, wealth transfer, and incapacity planning for families, business owners, and high-net-worth individuals. James has more than 25 years of experience and is a Trust and Estate Practitioner and member of STEP.

Date Last Reviewed: September 5, 2026

Legal Disclaimer: General legal information for California readers. Not legal advice. No attorney-client relationship is created by reading this article. Outcomes depend on facts, documents, timing, and governing law. Representation begins only after a signed engagement agreement.

IP Disclosure: The Law Office of James Burns name, service descriptions, and original editorial content are proprietary intellectual property. No portion of this article is a guarantee, solicitation for a particular result, or a substitute for individualized legal, tax, financial, or medical advice.